ZnS quantum dots@multilayered carbon: geological-plate-movement-inspired design for high-energy Li-ion batteries

Nowadays, much progress has been made in designing practical high-energy-density anode materials for lithium-ion batteries (LIBs). However, during repeated charge-discharge cycles, high-energy-density anode materials usually undergo large volume changes, which cause limited cycle life. The situation would be worse, when anode materials have high tap densities and low porosities. Here, inspired by a fact how Earth can release its inner stresses to maintain its structural stability through geological plate movements, a novel slippage-strategy is proposed to tackle the above problem. We fabricate a ZnS quantum dots@multilayered N-doped carbon matrix (ZnS-QDs@mNC), where ZnS quantum dots are well dispersed in N-doped carbon nanosheets, which are assembled into micro-sized particles by intertwined overlapping. In situ transmission electron microscopy demonstrates that carbon nanosheets of ZnS-QDs@mNC could slide against each other during lithiation, just as geological plate movements, which can help make a full use of the limited gaps between carbon nanosheets to reduce the volume expansion of ZnS-QDs@mNC anode to only 6.5% (far below the industrial acceptable value of ~30%). As a result of the structural stability, ZnS-QDs@mNC with a high tap density of 0.86 g cm-3 and a low total pore volume of 0.092 cm3 g-1 demonstrates excellent Li-storage properties, even when the areal capacity is increased to 1.82 mAh cm-2.